Working in underground environments such as tunnels or other underground excavations can be dangerous. Underground environments are associated with a special set of potentially life threatening conditions that include cave-ins, collapsing tunnel structure, exposure to toxic gases, and the like. As such, prevention and detection of these conditions are of paramount concern.
An underground environment, however, poses special challenges that must be addressed to successfully detect and prevent hazardous conditions. Technologies that function well above the ground, such as Global Positioning System (GPS), mobile phones, visual observation, and the like, do not function well below ground. This makes it difficult to assess a potentially dangerous situation in the underground environment.